Santa Claus came early to San Francisco this year, but he forgot his long pants.

As did quite a few of the hundreds of other Santas, and several of their helpers, who gathered by the Christmas tree in Union Square on Saturday.

The Santas were kicking off the start of this year's SantaCon, a worldwide event that features a daylong bar crawl that sends many of its participants to the naughty list.

The jingling bells, holiday-colored sequins, mistletoe and fake, cottony beards met in Union Square before heading off to the bars in various other neighborhoods throughout the city. Many of the Santas brought with them toy donations for San Francisco Fire Department's toy program, even as they mugged for photos, sipped beer, smoked joints and led the crowd in chants of "Ho, ho, ho!"

"You can just feel that everyone is having a good time," said 47-year-old Emily Salmon-Pezely, a first-time Santa. "It's just silly and enjoyable."

Santas continuously poured into the streets in what SantaCon participants called "the red tide," flowing out of BART stations, creating lines to get into nearby bars, and jamming into liquor stores. Dotting the sea of red-and-white felt hats were people dressed as Santa's lady helpers, elves, angels, penguins and gingerbread men.

Marisol Esparza, 39, of San Jose chose to be a snowman this year. "I'm always different," she said.

Esparza said she planned to join this year's SantaCon after she had a blast at last year's event, despite the rain and chilly air.

This year's event was sunny and warm after a record-breaking cold snap, leaving many participants sweating in their heavy Santa suits. But Chris Ripps, decked in a festive sleeveless holiday sweater vest and white fuzz-trimmed red shorts, said he loved having the opportunity to get out and enjoy the nice weather.

Ripps, a first-time SantaCon participant and longtime observer, expressed amazement at the sheer number of costumed revelers this year. He estimated that at least 1,000 had milled through Union Square before heading off to their drinking destinations.

"This is San Francisco expressing itself," the 48-year-old city resident said. "It's a way for us to celebrate our holiday spirit."

To the likely chagrin of Fox News' Megyn Kelly, who famously said on her show last week that Santa was white, there were Santas of all colors present Saturday, including one with his face painted green and another with his chest painted red. Carlyle Colby, who is black, laughed about Kelly's statement as he sat watching the crowd.

"Take a look at this Santa. What do you think?" he said, gesturing to himself. "I say this is the best-looking Santa you've ever seen. "

Colby, 50, was filming San Francisco's SantaCon for the AXS TV show "Art Mann Presents," which documents public parties and "a lot of drunk people," he said. Colby said he's followed SantaCons in Philadelphia, Reno and Portland, Ore., and this was his second San Francisco SantaCon.

"San Francisco's is beautiful because it's 65 degrees," he said, noting that he's already caught a few Santas "prepping" for the bar crawl with sips of drinks here and there. "This one's pretty cool."